1. Field of the Invention
The present invention relates to a medical instrument used in the medical field for assisting the patient""s breathing, and more particularly, to a modification of a medical instrument called airway which improves the subsidence of the root of the patient""s tongue to procure an air passage in the larynx.
2. Description of the Related Art
In a normal person, an air passage is secured in the larynx even when a person sleeps on the back so that air can flow through the rear of the root of the tongue to permit breathing without difficulty (See FIG. 8(i)). In a person with consciousness disorder, however, muscular tonus will disappear so that while sleeping in the supine position the root of the tongue will subside and thereby obstruct the passage of air, that is, the laryngeal airway with the result of causing breathing difficulty (See FIG. 8(ii)). This will inevitably result in a deterioration of the pathological condition.
In such a case it is necessary to provide the necessary air passage for breathing (that is, to secure an airway) by some means or other to permit undisturbed breathing. The device that is extensive used in such cases consists, as shown in FIG. 7, of an umbrella-shaped retainer (54) which is used for operating the device and which protrudes from the mouth, a straight air-conducting part (53) which leads from said umbrella-shaped retainer to the interior of the oral cavity, and a curved intra-oral insert (52) which is continuous with said straight air-conducting part (53). With a section generally shaped in the form of Roman I, it uses recess cavities (55, 55) to provide spaces for breathing on both sides. In other words, it is a medical instrument (51) called an xe2x80x9cairway.xe2x80x9d Said instrument (51) is inserted from the month into the larynx to lift up the root of the tongue (A) and thereby secure an air passage (See FIG. 8 (iii)).
Since the aforesaid medical instrument is not necessarily adapted to the shape of the tongue its use will, in certain cases, result in an unnatural condition. In other words, while, under some conditions, tongue which is a bundle of muscles may change its shape it will, in general, describe a natural curve and not assume an unnatural undular pattern. The aforesaid medical instrument, however, is bent at a steep angle after its transition of the extra-oral part to the intra-oral part in the portion leading from the straight air-conducting section to the curved intra-oral insert. As the aforesaid curved intra-oral insert is curved at a steep angle its bet and curved parts tend to apply pressure to the tongue in the direction of the root of the tongue.
Moreover, the aforesaid medical instrument is difficult to insert into the laryngeal region. In other words, said instrument has a particular fixed shape as has been explained herein above. When it is inserted, its bent and curved parts will therefore hit against various parts of the mouth such as, for example, the lips, incisors, the tongue or the palate, and thus be extremely difficult to handle.
Furthermore, the aforesaid medical instruments present difficulty in the withdrawal of sputum. In other words, the insertion of a suction tube can take place from either side of the recessed parts provided on both sides of said instrument with a section generally shaped in the form of a Roman I. However, since said instrument has a particular fixed shape as explained herein above, the suction tube will impinge on its bent and curved parts and will thus be incapable of being inserted farther to the back of the throat.
Furthermore, the aforesaid medical instrument is not capable of lifting up the root of the tongue to an adequate extent. In other words, since the object of this type of instrument is to secure an air passage by inserting the previously described instrument having a particular fixed shape between the tongue and the palate, the space provided as an air passage will be determined by the cross-sectional size of said instrument. When, for this purpose, the section of said instrument is made large in a deliberate attempt to ensure that the root of the tongue is lifted up to an adequate extent, a new problem will arise in that it will be difficult to insert the aforesaid instrument because of its particular fixed shape.
Moreover, the aforesaid medical instrument is difficult to clean after use. In other words, in view of the problems associated with the cleaning and disinfecting of the medical instrument in terms of the growth of bacteria the effectiveness of the disinfectant will be substantially impaired in the presence of residual protein matter residing on the surface of the instrument and bacterial growth will be facilitated. The aforesaid instrument, however, has a number of recess cavities that are difficult to clean because of its Roman I shaped section as explained herein above.
In order to resolve these difficulties, the inventor has, as a result of intensive investigation, created an arrangement of two strips curved as a gentle angle in the lengthwise direction in order to facilitate insertion into the laryngeal area and suited to the curvature of the tongue in such a manner as to provide a space passing between the strips in the lengthwise direction by positioning the strips separately from each other. Furthermore, the aforesaid two long and narrow strips are arranged in such a manner that the extent of separation of their anterior parts (on the side of the root of the tongue) can be adjusted by providing a spindle to couple the two strips in a freely movable manner.